Radio frequency identification (RFID) devices, also sometimes known as inlays, include an integrated circuit and an antenna. An RFID inlay may be used directly in some applications and in others undergo one or more manufacturing operations in order to complete the RFID tag, label or other enclosure housing the RFID device.
RFID tags and labels are widely used to associate an object with an identification code. RFID tags and labels generally have a combination of antennas and analog and/or digital electronics, which may include, for example, communications electronics, data memory, inputs, outputs and control logic.
In many applications it is desirable to reduce the size of the electronics as small as possible. In order to interconnect the small chip (integrated circuit) of the RFID device with the antenna, an interposer (sometimes referred to as a “strap”) may be used to facilitate manufacturing. An interposer may include conductive leads or pads that are electrically coupled to the contact pads of the chip for coupling to the antenna. The interposer pads provide a larger effective electrical contact area than an integrated circuit, which must be precisely aligned for direct placement without an interposer. The larger area provided by the interposer reduces the accuracy required for placement of chips during manufacture while still providing effective electrical connection.
RFID devices may be active, which include a power source (such as a battery), or passive, which do not. In the case of passive RFID devices, in order to retrieve the information from the chip, an RFID reader sends an excitation signal to the RFID device. The excitation signal energizes the RFID device, which transmits the stored information back to the reader. The RFID reader receives and decodes the information from the RFID device. In general, RFID devices can retain and transmit enough information to uniquely identify individuals, packages, inventory and the like.
Many items in the marketplace are packaged, singly or in bulk, in a container for shipping and/or storage. The manufacturers, distributors, retailers, and/or customers often use RFID devices to identify the containers at various points throughout the distribution chain of the items. Some such items may be sensitive to one or more environmental conditions such as temperature (i.e., heat or cold), humidity, chemicals, biological elements, radiation, light, liquid, a physical condition (e.g., pressure) or other condition. Consequently, it is important to the manufacturers, distributors, retailers, and/or customers of such items to determine whether the items have been exposed to any undesirable environmental conditions that may affect the item's use or desirability. In addition, it would desirable to make such determination in a cost effective and efficient manner using RFID devices and RFID readers already in use to track the location of such items. These and other advantages may be provided by one or more embodiments of the present invention.